It is either bugged or Blizzard has internally changed the names of spells to support the new talent system. What I have found is that the internal name of the warlock spell "Immolate" is "Corruption".

I basically have a mini addon to call SetBinding to implement all of my key bindings. On live, the following works

Code:

/script SetBindingSpell("3", "Immolate")

This would bind Immolate to key 3. On MOP Beta, I have to do the following to bind Immolate to key 3

Code:

/script SetBindingSpell("3", "Corruption")

Another is to use Shadow Bolt to bind Incinerate. I'm finding this out by using the following function and passing in spell book ids.

Code:

function PrintName(inputIndex)
local skillType, spellId = GetSpellBookItemInfo(inputIndex, BOOKTYPE_SPELL)
if (spellId ~= nil) then
DEFAULT_CHAT_FRAME:AddMessage(spellId)
end
local name, rank, icon = GetSpellInfo(spellId)
if (icon ~= nil) then
DEFAULT_CHAT_FRAME:AddMessage(icon)
end
if (name ~= nil) then
DEFAULT_CHAT_FRAME:AddMessage(name)
end
end